Pathogenicity of coccidia in Japanese quail (Coturnix coturnix japonica).

Coccidia were recovered from a field outbreak in commercially raised Japanese quail from South Carolina. After propagation in unmedicated quail, the culture was identified as a mixture of approximately 65% Eimeria uzura, 33% E. tsunodai, and 2% E. taldykurganica. Several pure cultures of E. uzura were obtained by single oocyst isolation. A micropyle was not present in all oocysts; thus, it is not a reliable taxonomic characteristic for identification of E. uzura. Neither the mixed culture nor the E. uzura isolates were infective for Bobwhite quail, Chukar partridge, pheasants, chickens, or turkeys. Seventeen-day-old quail were inoculated with various doses of sporulated oocysts ranging from 5 x 10(2) to 5 x 10(5) of the mixed culture and 1 x 10(3) to 1 x 10(6) of E. uzura. The rate of weight gain was depressed at 3 or 4 days postinoculation (DPT) with as few as 5 x 10(2) oocysts/quail of the mixed culture. As few as 1 x 10(3) oocysts of E. uzura produced a weight loss. Some individual quail had depressed packed cell volume and plasma pigment compared with levels in the uninoculated controls. Plasma protein was not affected. Young quail (3 days old at inoculation) were more susceptible than 17-day-old quail. Infection did not adversely affect body weights of adult quail, although egg production was reduced. Mortality was seen only with the mixed culture (100 and 8% in 3- and 17-day-old quail given 5 x 10(5) oocysts, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)